Why Do I Get Lightheaded During Exercise?

Susan Street

About the Author:

Susan Street

Susan Street has been a published writer since 2001, specializing in health, nutrition, fitness and life-improvement articles. She holds an Associate of Arts in business administration, has additional educational background in nutrition and is also a certified personal trainer with the National Exercise and Sports Trainers Association (NESTA).

A woman is feeling light headed at the gym.
(Image: BartekSzewczyk/iStock/Getty Images)

It is common to occasionally experience lightheadedness during rigorous exercise. If left untreated, this dizzy feeling can lead to fainting, which may result in serious injury. If you begin to get lightheaded, stop exercising immediately. Before resuming your workout regimen, try to identify the cause of the lightheadedness and a reasonable solution. Although the exact reason can be difficult to pinpoint, there are a few common causes to consider.

Low Blood Sugar

Many people tend to eat less prior to a workout to prevent the discomfort of a full stomach. This especially applies to people who work out in the morning and assume the dinner from the night before will supply enough energy to exercise. The meal you ate eight to 12 hours before a workout will not provide adequate energy. You should eat a small snack high in carbohydrates within an hour before a workout. Bananas, whole grains, energy bars, milk and juice are excellent options to raise your blood sugar and avoid feeling lightheaded. Low blood sugar is a major cause for dizziness and fainting, so it is vital to fuel your body properly prior to exercising.

Dehydration

Sweating and activity cause your body to lose water, and if you are losing more than you put in, you will become dehydrated. Drinking a bottle of water at the gym may not be enough if you are already dehydrated prior to beginning your workout. If you feel thirsty at any point during the day, you should drink water or other clear liquids to keep your hydration up. Staying hydrated throughout the day could alleviate lightheadedness during exercise. Dehydration can also cause low blood pressure in some people, leading to severe lightheadedness and fainting.

Overexertion

When you feel lightheaded during a workout, it may be your body’s way of saying “slow down.” The reason for exhaustion may be due to the workout being too intense, stress, underlying illness or simply a lack of energy. Clinical Exercise Physiologist Chris Dunn also points out that overheating in combination with overexertion can cause dizziness while exercising and should not be ignored. Overexertion may also cause muscle weakness, headaches, cramps and heart palpitations. If you suspect you have pushed yourself too hard, slow your pace and drink water. You may also want to sit down and elevate your feet to improve circulation, which will help alleviate the lightheaded feeling.

Underlying Health Issues

Occasionally, lightheadedness while exercising can be caused by an underlying health issue such as heart disease. If you experience pain in your arms, jaws or chest, stop exercising immediately as this could be a sign of a heart problem. Another health issue that could cause lightheadedness during exercise is decreased lung function due to a blood clot, infection or other lung-related illness. Stop exercising if you feel like you are unable to get a good breath or if you have pain in your lungs. In these instances, it is advisable to seek medical care as soon as possible. Even in the absence of additional symptoms, lightheadedness warrants a trip to your doctor for a checkup to ensure that you are able to exercise safely.